Pirates clutching knives and AK47s boarded a supertanker moored off Basra in the latest of a series of seaborne robberies in the Persian Gulf.In recent weeks there have been a number of audacious attacks on ships waiting to load at the city's overstretched terminals, raising concerns about the safety of oil exports and adding piracy to the area's list of security threats.In the most recent incident, three men boarded the tanker in the early hours of Wednesday morning.

A marble masterpiece in private hands for 400 years and now attributed to the Renaissance sculptor Donatello went on public view yesterday for the first time.The bas-relief of the Madonna with 13 cherubs is said to have come from the tomb of St Catherine of Siena in Rome's Santa Maria Sopra Minerva. The work is thought to have been sculpted by Donatello in 1430 and 1431, but all trace of it was lost after the tomb was dismantled in the 1570s.